Granular resins are supplied in the forms of emulsions, microgels, non-aqueous dispersion resins (AND resins), powder resins and the like, and have been watched with keen interest in paint industries, especially in aqueous paints, high solid paints and powder paints, because of measuring up to the social requirements of economization of natural resources, energy saving and conservation of good surroundings.
However, such a resin is usually crosslinked so that the characteristics of the resin particles can be fully developed, and therefore, when the granular resin is used alone, it is unable to yield a uniform or excellent film and the resulted film has a serious drawback of deficient film appearance.
Even when the granular resin is combined with a soluble type resin, there is a case that the viscosity of the mixture is unduly increased as compared with that of said soluble type resin alone, due to the considerable interaction between the surfaces of said granules and the soluble type resin. Therefore, great care is often required in the actual use of such combination of resins.
Furthermore, since the characteristics of crosslinked resins are greatly influenced by the nature of surfactant used, crosslinking degree and combination of constituting monomers and the like, heretofore proposed crosslinked resin particles are hardly dispersible in such medium as aliphatic hydrocarbons, high boiling aromatic hydrocarbons, high polar solvents or the like and once they form agglomerates, hardly get loose back to the primary particles. Thus, considerable difficulties are always encountered in the actual applications thereof.
Therefore, an object of the invention is to provide novel composite resin particles which are free from the drawbacks of the abovementioned resin particles. Thus, a principal object of the invention is to provide novel composite resin particles which can be used either singularly or in combination form with any other resins customarily used in paint industries, to give excellent coating compositions with good application characteristics and storage stability and capable of resulting in a uniform coating with excellent appearance.
An additional object of the invention is to provide novel composite resin particles having self-catalytic function in crosslinking or having excellent biological activities.